WorldPac (Pack of 4) E Track Fitting with 9mm Diameter O-Ring Stainless Steel - Extreme Heavy Duty O Ring fitting to fit on E or A track FOUR Plate Base with 7,500 LBs Capacity Heavy Duty 9mm Thick O Ring with 2.25" Diameter Ring 5/32" thick plate held together with single 3/16" rivets Zinc Plated Gold Chromate Finish Base for Corrosion Resistance